Question

a semicircle is cut along its breadth from a rectangular sheet of paper having length 30 cm and breadth 28 cm find the area left
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Answer 1

Answer:

Step-by-step explanation:

Case1: when the sheet is folded along its length :

In this case, it forms a cylinder having height h1=18 cm and the circumference of its base equal to 30 cm.

Let the radius of its base be r1. Then,

2pi r1=30

r1=15/pi.

V1=pi r^2 h=pi*(15/pi)^2 cm3=4050/pi.cm3

Case.2

When the sheet folded along its breadth :

Heights h2=30cm and the circumference of its base equal to 18cm.

Let the radius be r2. Then,

2pi r2=18=(9/pi)

V2=pi r^2 h=(pi*(9/11)^2) cm^3 =2430/pi cm^3.

V1/v2=(4050/pi*pi/2430)=4050/2430=5/3